Prediction of Flow Regimes in Horizontal Tube-Side Condensation

Recent experimental evidence firmly supports previous speculations that prediction of flow regimes is crucial for accurate estimation of heat transfer coefficients in tithe-side condensation. Although it has been recognised that two distinct condensation mechanisms are possible, corresponding to the annular and the stratified flow patterns, the need for criteria for determining which mechanism to apply under given process conditions has been just recently recognized. A visual investigation of condensation in a horizontal glass tube indicated that the Baker flow regime map did not provide a realistic picture of controlling regimes in condensation. A new approach based on simple force ratios greatly improved prediction for all existing data. Further improvement by means of a two-parameter flow regime map is shown in a qualitative form.